Helping people with computers... one answer at a time.
These days, digital camera often take pictures that are much larger than our computer screen's resolution. I'll review some techniques to deal with that.
Ending up with a picture that is "too big" is common lately. Many digital cameras and even phones take photographs at resolutions that exceed that of our computer screens.
Getting a picture that's more easily viewable on your computer screen - or that of the people with whom you might share your picture - is actually fairly straightforward with almost any image editing application.
In this video from an Ask Leo! webinar on Photo Manipulation, I'll show a couple of techniques to make large images visually smaller.
Download the video: webinar8-1-photo-too-large.mp4 (42M).
Dealing with a picture that is visibly 'too large'. In this segment, I'm going to take an image, in fact, you'll see that I've got a couple of images on screen right now. We're going to work with this coffee cup image first. This is a picture that I took with my cell phone not that long ago. You can see now that FastStone has set it up to be full screen. One thing I want to point out, and if I do this correctly, it will look proper. Up in the upper-left hand corner, you'll see that FastStone is showing some information about the picture. The picture is 3264 x 1952 pixels in size. The screen we're using here; the screen resolution that I use for these videos is 1280 x 720 which is basically the moral equivalent of 720p high definition television.
So the picture, as you can see, is in fact much larger than the screen. It's also showing the physical size, 1.6MB 37% that it's showing there towards the right is what FastStone has scaled the picture to be to show it to you full screen. So when we take a look at this we're actually seeing the photo at only 37% of its actual size. FastStone lets you go to 100% pretty quickly; all you really need to do is click and hold and you can see now that as we move around the entire picture, the picture's actually quite large. And as you can see, it will not fit on the screen.
The problem that many people experience is they will take a photo with their phone or with their camera, not do anything to it and just send it to a friend. Now most image viewing applications will do exactly as FastStone has shown here. They will automatically reduce the displayed image so that it fits on the screen or the window. But not all do and in fact, we do hear from time to time from people who don't understand why the picture that they're looking at instead of being say, in this particular case, the full coffee cup, only ends up looking like one corner of it and they end up having to do all sorts of scrolling to see the picture.
So what we need to do is take this image that's 3200 pixels by 1900 pixels and perform what's called a resize operation on it. Now I'm using FastStone for all of these operations because a) it's free and b) it's a pretty nifty, powerful program but also it just shows off the concepts fairly well. You can do the things I'm about to display in programs, like MS Paint, which actually comes with Windows but it tends to be somewhat more limiting. I just think FastStone is a pretty nifty way to go. More than anything though, even if you don't elect to use FastStone are the concepts that we're talking about here.
So with FastStone, the easiest way to take a picture like this and resize it is to take the mouse pointer and hover it over the left-hand side. There, you'll see several options - one of which is in fact something called Resize/Resample. You can hit CTRL R to do this, but I'm going to do this with the mouse just to make sure things are appropriately visible and you can see where I'm headed.
So, I'm going to click on Resize/Resample. Now, you have several options; several different ways to define how you want this picture to be smaller. You can actually go ahead and specify a new pixel size; you can specify a percentage, so if I wanted to make the picture say, half the physical size than it was before, I can say that here by entering in 50%. You can do Print Size but I'm actually going to have you sort of avoid that for the time being and the reason I say that is print size depends on this other thing here called dots per inch. 72 is actually not an unreasonable DPI for displaying on the screen and in fact, the full image would probably be something like 45 inches wide if I were to show it full screen, if I actually had a screen that large. Printing can be either 300 or 600 DPI. It may or may not be accurate, it's just not one of those things that's not particularly helpful this stage of the game. And finally, I do want to point out that FastStone does include a bunch of standard sizes. Things like 1200 x 800, I'm sorry, 1280 x 800; 800 x 600; sizes that you probably already recognize and use and including half and double.
And in this particular case, what I'm going to do is take it to 33%. Now, the reason I'm choosing 33% is that if you take a look (I'll go back and change it to 50) if you take a look at the new size, 1632 x 976, you'll see that is actually still larger than my screen. Remember, my screen is 1280 x 720. So I'm going to take it down to 33%. 33% gives me something that is slightly smaller than my screen. I can go a little larger; I can play with it all I want but 33 is a nice number to just give it a shot and I'll hit OK.
Now, what you've noticed that the picture has gotten a little bit smaller but if you'll take a close look, what you'll see in that upper-right hand corner, upper-left hand corner is that the dimensions of the picture have changed to the 1077 x 644; it's now a little bit smaller it's actually 1.6 MB (is still incorrect because we haven't saved anything) but what's most important here is it's now showing 100%; in other words, FastStone did not have to reduce the size of this picture in order to display it. It is simply displaying the picture at 100% resolution and anybody who happens to have a screen that's at least 1077 x 644 can see the entire picture at full resolution. Now, what we want to do, of course, is save our results. So the thing we do over here is off on the left again is the Save As menu (you can type CTRL S to make this happen). We're going to Save As and I'm going to give it a new name, coffeecupsmaller, and you'll notice that it came in as .jpg file and we're going to save it as a .jpg file and that's it! And in fact, if we go back to the list of pictures in that folder, you'll see the original and then coffeecupsmaller, the smaller version that we just created. The coffeecupsmaller, double-clicking on it, gives us 100% resolution of the picture. Double-clicking on the other one gives us the full picture, but as you can see, once again, it's been scaled down to 37% of the original picture. If someone doesn't have the ability to automatically scale their pictures then the smaller one, the visibly smaller one has the smaller resolution in terms of pixel dimensions so that's the one you want to send.
So resizing pictures is one approach to making pictures visibly smaller. I also want to talk about a different approach, resizing a picture by using cropping. So in this particular picture, a picture I took last summer of one of the ferries out here on Puget Sound, you can see there's actually a fair amount of space around the ferry itself. We take a look at the upper-left again, we can see that the actual scaling this time is 25%; in other words, the actual photograph, if it were displayed at 100% would be four times bigger than this and in fact, using FastStone, I'll quickly zoom in here and you can see that at four times what we saw originally, the picture doesn't fit on the screen. So one approach is you can now use what is called the Crop tool. They call it a Crop board. All that cropping really means is you get to define a rectangle that is the result you want. Everything that is outside of that rectangle is actually removed from the picture. So I've selected just the ferry and a little bit of background here and I'm going to go ahead and say Crop. So the net result now is a picture that contains only the ferry and the background that I selected. As you can tell, the ferry itself is somewhat larger and it's a little bit more detailed even in this reduced view. And it's important to note that this is in fact still a reduced view; even though I've cropped the photo, I haven't cropped it small enough to fit on the entire screen. We've gone from 25% magnification or reduction I should say to 44% meaning that FastStone only had to reduce this picture to 44% of my original in order to make the whole thing fit.
So, we'll actually end up taking one more step and going ahead and doing a resize on the photo to make it fit. This time, I'm going to go ahead and choose 40%; again, I'm choosing that fairly randomly, I'm simply choosing that so the resulting size will be something that fits in its entirety on the screen I happen to have in front of me. FastStone does its resize thing and you can see that the picture became just a little bit smaller, but once again and it is at 100%, meaning that if you were now to save and email this photo to someone else, they would actually be able to see this in its entirety on their screen without their viewing software having to make any modifications. Like before, we will end up saving this using Save As. In this particular case, the original file came in as NEF format which I'm going to explain in a separate segment. But we're going to save this as ferry_cropped and now if you take a look at the pictures we have in this folder, you can see that the original ferry photo shows a lot more background to it than the cropped version. That allows you to take a photograph and not only reduce its visual siz,e but also with cameras today having such incredibly high resolutions, you can, it's a way of cropping out distractions and focusing the photograph on the element that you want. If I wanted to focus on the front of the ferry only - let's go ahead and do that...interesting, I'm looking at my original here. I'm double-clicking on it, but FastStone believes we're still actually working on that photograph and therefore is showing me the results of all the edits I've made so far, even though I have saved a copy of this by another name. At this point, rather than figure out how to make FastStone do the right thing, I already know that if I close FastStone by clicking on the correct X and start it up again, it actually resets its concept of what we're doing.
So, where I was headed is simply that if wanted to take this image and focus on only one portion of it, say a small portion of it by say, zooming in on the front of the ferry boat here, one way to do so is to fire up the crop board and crop to just that specific area. Now if I crop, the image that I have is much larger, much more focused on the specific element that happened to be somewhere in my picture. It is still, after all this, too large to fit on my screen. But by cropping first and resizing later, you end up with the highest possible detail in the resulting photograph. So I wanted to point that out real quick that cropping photographs sometimes is a very useful way to cut out a lot of noise and you'll find that a lot of professional photographers end up doing exactly that. With the high resolutions on so many cameras today, it's very easy to take a large picture and then crop it down to the specific item that you are interested in portraying; at the same time, you end up with a smaller, more easily visible photograph. So, that was resolution.